Association of asthma with polymorphisms in the cysteinyl leukotriene 2 receptor

ABSTRACT

Polymorphisms in the cysteinyl-leukotriene receptor 2 gene and their association with asthma are described.

FIELD OF THE INVENTION

[0001] The present invention relates to polymorphisms in the cysteinyl-leukotriene receptor 2 gene and asthma.

BACKGROUND OF THE INVENTION

[0002] Asthma is one of the most frequent chronic diseases with a prevalence of up to 10% (Jarvis and Burney, Br. Med. J. 316:607 (1988)). Both genetic and environmental factors contribute to the overall phenotype. Family studies have shown an increased frequency of asthma in first-degree relatives (Marsh, Allergol. Immunopathol. (Madr.) Suppl 9:60 (1981), Townley et al, J. Allergy Clin. Immunol. 77:101 (1986)). Environmental exposure to allergens, pollutants, and viral respiratory infections are important in the development of asthma (Boushey et al, Am. Rev. Respir. Dis. 121:389 (1980), Cookson and Moffat, Hum. Mol. Genet. 9:2359 (2000)). The interaction between the genetic and environmental factors in the pathogenesis of asthma is not fully understood. Asthma is the most common chronic childhood disease in developed nations and carries substantial direct and indirect economic cost (Lenny, Pediatr. Pulmonol. Suppl. 15:13 (1997)). The prevalence of asthma and other allergic diseases has risen over the past 2 decades (McNally, et al, Soc. Sci. Med. 46:729 (1998)) and the cost of treating the disease in United States is approximately US $6 billion per annum (Smith et al, Am. J. Respir. Crit. Care Med. 156:787 (1997)).

[0003] In view of the impact of asthma, better methods of identifying children at risk, and of assessing the efficacy of anti-asthma therapeis, would be beneficial.

SUMMARY OF THE INVENTION

[0004] A first aspect of the present invention is a method of identifying a subject at increased risk of asthma, by detecting the allelic forms of the A601G polymorphism in the Cysteinyl leukotriene 2 receptor gene. A person homozygous for the A allele is at increased risk for asthma compared to a subject with at least one G allele.

BRIEF DESCRIPTION OF THE FIGURES

[0005]FIG. 1 provides the sequence of the CysLT2 receptor gene (SEQ ID NO:1), with the start codon underlined (264-266) and stop codon underlined (1302-1304). The polymorphic sites are indicated by bold underlined text: coding SNP A601 G (864), noncoding SNP TSC3P1 (A/G at 2796) and TSC3P2 (A/G at 2960).

[0006]FIG. 2 provides the amino acid sequence (SEQ ID NO:2) encoded by the above nucleotide sequence, with the polymorphic amino acid (met/val) shown in bold underlined text.

DETAILED DESCRIPTION

[0007] Leukotrienes are a family of eicosinoids which form part of a much larger group of compounds synthesized from arachadonic acid. The cysteinyl leukotrienes (CysLTs), LTC4, LTD4, and LTE4, previously known as slow reacting substance of anaphylaxis, or SRS-A, are derived from arachidonic acid via oxygenation and dehydration by 5-lipoxygenase followed by specific glutathione addition by LTC4 synthase.

[0008] The CysLTs mediate their biological actions through two pharmacologically defined G-protein-coupled receptors (GPCRs), named the CysLT1 and CysLT2 receptors. (See WO 01/59105 (Glaxo Group Limited); Nicosia, Monaldi Arch. Chest Dis. 54:242 (1999); Takasaki et al., Biochem. Biophys Res. Commun. 274:316 (2000); Heise et al., J. Biol. Chem. 275:30531 (2000); Nothacker et al., Mol. Pharmacol. 58:1601 (2000); Nicosia et al., Pulm. Pharmacol. Ther. 14:3 (2001)). LTB₄ is produced mainly by macrophages and neutrophils and stimulates neutrophil chemotaxis, enhances neutrophil-endothelial cell interactions and stimulates neutrophil activation leading to degranulation and the release of mediators, enzymes and superoxides. The cysteinyl leukotriene receptors respond to LTD₄, LTE₄, LTC₄ and LTF₄, however the occurrence in vivo of LTF₄ is unclear.

[0009] Cysteinyl leukotrienes contract airway smooth muscle, increase microvascular permeability, stimulate mucus secretion, decrease mucociliary clearance and recruit eosinophils into the airways. The CysLT2 receptor has been documented pharmacologically to be expressed in guinea pig trachea and ileum, ferret trachea and spleen, sheep bronchus, and human pulmonary and saphenous vein preparations. At the CysLT2 receptor subtype, the agonist potency rank order is LTC4=LTD4>>LTE4 and LTE4 is a partial agonist.CysLT1 receptor-specific leukotriene receptor antagonists, such as montelukast, zafirlukast and pranlukast are currently used to control bronchoconstriction and inflammation in asthmatic patients. CysLT1 is mainly detected in lung smooth muscle cells, macrophages, spleen and peripheral blood lymphocytes and has not been detected in heart.

[0010] As used herein, a “genetic subset” of a population consists of those members of the population having a particular genotype. In the case of a biallelic polymorphism, a population can potentially be divided into three subsets: homozygous for allele 1 (1,1), heterozygous (1,2), and homozygous for allele 2 (2,2). A ‘population’ of subjects may be defined using various criteria, e.g., individuals being treated with a certain therapeutic or diagnosed with a certain medical condition, individuals of a defined ethnicity or demographic group, etc.

[0011] As used herein, a subject that is “predisposed to” or “at increased risk of” a particular phenotypic response based on genotyping will be more likely to display that phenotype than an individual with a different genotype at the target polymorphic locus (or loci).

[0012] “Genetic testing” (also called genetic screening) as used herein refers to the testing of a biological sample from a subject to determine the subject's genotype; and may be utilized to determine if the subject's genotype comprises alleles that either cause, or increase susceptibility to, a particular phenotype (or that are in linkage disequilibrium with allele(s) causing or increasing susceptibility to that phenotype).

[0013] “Linkage disequilibrium” refers to the tendency of specific alleles at different genomic locations to occur together more frequently than would be expected by chance. Alleles at given loci are in complete equilibrium if the frequency of any particular set of alleles (or haplotype) is the product of their individual population frequencies A commonly used measure of linkage disequilibrium is r: $\begin{matrix} {r = \frac{{\hat{\Delta}}_{AB}}{\sqrt{\left( {{\overset{\sim}{\pi}}_{A} + {\hat{D}}_{A}} \right)\left( {{\overset{\sim}{\pi}}_{B} + {\hat{D}}_{B}} \right)}}} \\ {where} \\ {{{\overset{\sim}{\pi}}_{A} = {{\overset{\sim}{p}}_{A}\left( {1 - {\overset{\sim}{p}}_{A}} \right)}},{{\overset{\sim}{\pi}}_{B} = {{\overset{\sim}{p}}_{B}\left( {1 - {\overset{\sim}{p}}_{B}} \right)}},{{\hat{D}}_{A} = {{\overset{\sim}{P}}_{AA} - {\overset{\sim}{p}}_{A}^{2}}},{{\hat{D}}_{B} = {{\overset{\sim}{P}}_{BB} - {\overset{\sim}{p}}_{B}^{2}}}} \\ {{\hat{\Delta}}_{AB} = {{\frac{1}{n}n_{AB}} - {2{\overset{\sim}{p}}_{A}{\overset{\sim}{p}}_{B}}}} \end{matrix}$

[0014] nr² has an approximate chi square distribution with 1 degree freedom for biallelic markers. Loci exhibiting an r such that nr² is greater than 3.84, corresponding to a significant chi-squared statistic at the 0.05 level, are considered to be in linkage disequilibrium (BS Weir 1996 Genetic Data Analysis II Sinauer Associates, Sunderland, Md.).

[0015] Alternatively, a normalized measure of linkage disequilibrium can be defined as: $D_{AB}^{\prime} = \left\{ \begin{matrix} {\frac{D_{AB}}{\min \left( {{p_{A}p_{B}},{p_{a}p_{b}}} \right)},} & {D_{AB} < 0} \\ {\frac{D_{AB}}{\min \left( {{p_{A}p_{b}},{p_{a}p_{B}}} \right)},} & {D_{AB} > 0} \end{matrix} \right.$

[0016] The value of the D′ has a range of −1.0 to 1.0. When statistically significant absolute D value for two markers is not less than 0.3 they are considered to be in linkage disequilibrium.

[0017] The present studies investigated the presence of three polymorphisms in the CysLT2 receptor gene, and the occurrence of asthma.

[0018] Sample Composition and Clinical Evaluation

[0019] Asthma families were studied at 2 collection centers: (1) the Department of Medicine, University of Minnesota Medical School, Minneapolis, Minn. (Min); and (2) Department of Respiratory Medicine, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark (Den). In the selection of these families, at least two siblings with clinical asthma were required. The proband had the following criteria for the diagnosis of asthma: (1) at least 2 out of the 3 categories including of cough, wheezing, and dyspnoea should be recurrent and (2) a documentation of an increase in FEV by 15% of predicted value, minimum 300 ml) after a bronchodilator or (b) a positive methacholine inhalation challenge (PC₂₀ FEV₁<10 mg/ml). The following exclusion criteria were followed:

[0020] 1. Birth weight less than 4.4 pounds;

[0021] 2. Systematic vasculitis involving the lungs;

[0022] 3. Congenital or acquired pulmonary diseases at birth;

[0023] 4. Uncorrected congenital heart disease;

[0024] 5. Severe cardiac disease;

[0025] 6. Current medications that interfered with phenotypes that could not be stopped, such as beta blocking agents;

[0026] 7. Isolated occupation induced asthma.

[0027] All subjects were evaluated by using standard protocols. Baseline spirometry was performed by according to American Thoracic Society (ATS) criteria. Skin Prick Tests (SPT) for the common allergens (mites, animal, insects, pollen and mould) were conducted.

[0028] The Denmark collection was composed of 268 families, 985 samples with genotypes, 367 children with Physician's diagnosis of asthma (PDA), 120 with Bronchial hyper-reactivity (BHR) and 275 with atopic asthma. The Minnesota collection constituted 83 Caucasian families, 317 samples with genotypes, 168 children with PDA, 144 with strict asthma, 122 with BHR and 139 with atopic asthma.

[0029] In addition to the family samples, a matched Caucasian case control collection from North Carolina was also evaluated (one hundred cases and 100 controls, “asthma-1” collection). This collection is from Duke University Medical Center, Durham, N.C. The primary diagnostic criteria for this collection was a definite physician's diagnosis for the presence of asthma (PDA) or not asthma. Skin prick tests to common allergens and standard spirometric measurements were also evaluated in this collection.

[0030] Phenotypes:

[0031] The following phenotypes were evaluated. 1) PDA; 2) strict asthma, 2 or more classic symptoms (cough, wheeze and shortness of breath) and a positive methacholine challenge test or bronchodilator reversibility; 3) bronchial hyper-reactivity (BHR), positive methacholine response at or below 10 mg/ml of methacholine and 4) atopic asthma, physician's diagnosis and positive results on at least one skin allergen tests.

[0032] Genotyping:

[0033] DNA was isolated from whole blood or lymphoblastoid cell lines. The Single Nucleotide Polymorphisms (SNP) genotypes were generated using the 5′ nuclease assay with TaqMan® (Applied Biosystems, Foster City, Calif.) fluorogenic probes and the products were read on an ABI PRISM® 7700 Sequence Detection System (Applied Biosystems).

[0034] Statistical Analysis:

[0035] The association of the asthma related phenotypes with the markers are tested by transmission disequilibrium test comparing the frequencies of the alleles transmitted to affected children to those not transmitted using Transmit (Dudbridge et al, Am. J. Hum. Genet. 66:2009 (2000)), for the family data. Association analysis for the case control population was done using Fisher's exact test (Zaykin et al, Genetica 96:169 (1995)). Haplotype analysis of the family data was done using Transmit (Dudbridge et al, 2000) and by a method using EM algorithm for the case control data (Zaykin et al, “Testing association of statistically inferred haplotypes with discrete and continuous traits in samples of unrelated individuals, Human Heredity (in press)).

[0036] Hardy-Weinberg Equilibrium (HWE) Analysis:

[0037] The departure from HWE is tested using a Chi square test, by testing the difference between the expected (calculated from the allele frequencies) and observed genotype frequencies.

[0038] Linkage Disequilibrium (LD) Analysis:

[0039] The LD between two markers is given by D_(AB)=p_(AB)−p_(A)p_(B), where p_(A) is the allele frequency of A allele of the first marker, p_(B) is the allele frequency of _(B) allele of the second marker, and p_(AB) is the joint frequency of alleles A and B on the same haplotype. A commonly used measure of LD can be calculated as follows.

[0040] Where $\begin{matrix} {{\hat{\Delta}}_{AB} = {{\frac{1}{n}n_{AB}} - {2{\overset{\sim}{p}}_{A}{\overset{\sim}{p}}_{B}}}} \\ {r = \frac{{\hat{\Delta}}_{AB}}{\sqrt{\left( {{\overset{\sim}{\pi}}_{A} + {\hat{D}}_{A}} \right)\left( {{\overset{\sim}{\pi}}_{B} + {\hat{D}}_{B}} \right)}}} \end{matrix}$

[0041] nr² has an approximate chi square distribution with 1 df.

[0042] According to the present methods, a compound may be screened for variation in its effectiveness in treating asthma among genetic subpopulations of subjects. the phenotypic response of subjects to an asthma treatment may include the magnitude, duration, or occurrence of a positive response to treatment, or the magnitude, duration or occurrence of an unwanted side effect, or the absence of any response. Methods of correlating genotype with phenotypic response to treatment include administering the therapeutic to a population of subjects, obtaining biological samples from the subjects, genotyping polymorphic allelic sites as identified herein, and correlating the genotype of the subjects with their phenotypic response (e.g., response to therapeutic treatment).

[0043] Polymorphic alleles may be detected by determining the DNA polynucleotide sequence, or by detecting the corresponding sequence in RNA transcripts from the polymorphic gene, or where the nucleic acid polymorphism results in a change in an encoded protein by detecting such amino acid sequence changes in encoded proteins; using any suitable technique as is known in the art. Polynucleotides utilized for typing are typically genomic DNA, or a polynucleotide fragment derived from a genomic polynucleotide sequence, such as in a library made using genomic material from the individual (e.g. a cDNA library). The polymorphism may be detected in a method that comprises contacting a polynucleotide or protein sample from an individual with a specific binding agent for the polymorphism and determining whether the agent binds to the polynucleotide or protein, where the binding indicates that the polymorphism is present. The binding agent may also bind to flanking nucleotides and amino acids on one or both sides of the polymorphism, for example at least 2, 5, 10, 15 or more flanking nucleotide or amino acids in total or on each side. In the case where the presence of the polymorphism is being determined in a polynucleotide it may be detected in the double stranded form, but is typically detected in the single stranded form.

[0044] As is well known genetics, nucleotide and amino acid sequences obtained from different sources for the same gene may vary both in the numbering scheme and in the precise sequence. Such differences may be due to inherent sequence variability within the gene and/or to sequencing errors. Accordingly, reference herein to a particular polymorphic site by number (e.g., CysLT2R A601G) will be understood by those of skill in the art to include those polymorphic sites that correspond in sequence and location within the gene, even where different numbering/nomenclature schemes are used to describe them.

EXAMPLE 1 Primers and Probes

[0045] Marker Name: CysLT2R 3P1 (A>G)

[0046] Allele 1=A

[0047] Allele 2=G Probes: allele 1 = (SEQ ID NO:3) 6FAM-ACTAAGTCAGTCATCATACTAAACAAAAATCC-TAMRA allele 2 = (SEQ ID NO:4) VIC-ACTAAGTCAGTCGTCATACTAAACAAAAATC-TAMRA Primers: (SEQ ID NO:5) CysLT2R 3P1 A>G F GGGTGGAGGTGATATGGCATT (SEQ ID NO:6) CysLT2R3P1 A>G R TCTGTCTGTCATCATTCTGGTAGCT

[0048] All probes and primers were supplied at 100 uM in water.

[0049] Marker Name: CysLT2R 3P2 (A>G)

[0050] Allele 1=A

[0051] Allele 2=G Probes: allele 1 = (SEQ ID NO:7) 6FAM-TTGAGGATCCTTCAACACAAAAGCTGC-TAMRA allele 2 = (SEQ ID NO:8) VIC-TTGAGGATCCTTCA GCACAAAAGCTG-TAMRA Primers: (SEQ ID NO:9) CysLT2R 3P2 A>G F AGACAGACTCAAACCCTGTCAAGAC (SEQ ID NO:10) CysLT2R3P2 A>G R GCTTCATCGTCAGGTGAGTAATAGG

[0052] All probes and primers were supplied at 100 uM in water.

[0053] Marker Name: CysLT2R A601G (CysLT2R Met201Val)

[0054] Allele 1=A

[0055] Allele 2=G Probes: allele 1 = (SEQ ID NO:11) 6FAM-TGCTAAGCTGCAGACCATGAACTATATTGC-TAMRA allele 2 = (SEQ ID NO:12) VIC-CTAAGCTGCAGACCGTGAACTATATTGCC-TAMRA Primers: (SEQ ID NO:13) CysLT2R A601G A>G F CACATCATGCTTAGAGCTGAATCTC (SEQ ID NO:14) CysLT2R A601G A>G R CAGATAACAGATGCTGAGTGTGAAAA

[0056] All probes and primers were supplied at 100 uM in water.

EXAMPLE 2 Results

[0057] The above three markers were genotyped in the Denmark, Minnesota and asthma-1 collections, in the Cyslt2R gene. One coding polymorphism (A601G), and 2 noncoding SNPS (TSC3P1 and TSC3P2) that are 3′ to the coding polymorphism were genotyped.

[0058] Populations Studied:

[0059] (1) Minnesota: 91 families

[0060] (2) Denmark: 268 families

[0061] (3) Asthma-1: 200 cases and 100 controls (Phenotype PDA)

[0062] Den-Min: Combined analysis from Denmark and Minnesota.

[0063] The frequencies of different alleles are provided in Table 1 and the results of the association study are provided in Table 2. The allele frequency of CYSLT2R_A601G in Parents with and without asthma in the Denmark and Minnesota populations is shown in Table 3; in the Asthma-1 population, in Table 4. Table 5 shows linkage disequilibrium estimates.

[0064] Results and Discussion

[0065] The transmission dis-equilibrium test showed significantly lower transmission of the G allele of the marker A601G to the asthmatic children. This association was statistically significant in the combined Denmark and Minnesota families for physician's diagnosis of asthma (PDA), atopic asthma, and strict definition of asthma. The association was statistically significant in the Denmark families for PDA and marginally significant for atopic asthma. The frequency of the G allele was lower in asthmatics compared to non-asthmatics in the asthma-1 case control collection. The affected and un-affected parents (for PDA) from the Denmark and Minnesota collections were examined, and it was found that the frequency of the G allele was lower in affected parents compared to unaffected parents. The markers A601G and CYSLT2R-3P1 are in significant linkage dis-equilibrium (see Table 5) and the haplotype involving the allele G of A601G and allele A of CYSLT2R-3P1 shows significantly lower transmission to the affected children in the combined Minnesota and Denmark families for PDA (p=0.0032).

[0066] The A601G single nucleotide polymorphism was found to be associated with Asthma and related phenotypes, and does change the amino acid sequence of CysLt2R from Methionine to Valine at amino acid position 201. The G allele of this polymorphism was found to be associated with resistance to asthma. This polymorphism has been associated with decreased expression of the CysLT2R protein, and also the decreased affinity for leukotrienes to the receptor. This association suggests that compounds that block the CysLT2R receptor are useful for the treatment of asthma. TABLE-1 Frequency of the Alleles in Different Populations Marker Allele Minnesota Denmark DenMin Asthma-1 Pooled CYSLT2R_3P1 A 0.56 0.53 0.54 0.56 0.55 CYSLT2R_3P1 G 0.44 0 47 0.46 0.44 0.45 CYSLT2R_3P2 A 0.93 0 94 0.94 0.93 0.94 CYSLT2R_3P2 G 0.07 0.06 0.06 0.07 0.06 CYSLT2R_A601G A 0.97 0.97 0.97 0.98 0.97 CYSLT2R_A601G G 0.03 0.03 0.03 0.02 0.03

[0067] TABLE-2 Results of the Association Study Phenotype Population Marker ASTHMA ATP_ASTH BHR PDA Minnesota CYSLT2R_3P1 0.315 0.307 0.874 0.676 Minnesota CYSLT2R_3P2 0.295 0.520 0.822 0.528 Minnesota CYSLT2R_A601G 0.092 0.435 0.472 0.138 Minnesota CYSLT2R_3P1 0.817 0.777 0.416 0.846 Denmark CYSLT2R_3P2 0.610 0.392 0.743 0.132 Denmark CYSLT2R_A601G 0.179 0.057 0.100 0.009 Denmark CYSLT2R_3P1 0.535 0.567 0.576 0.901 Den-Min CYSLT2R_3P2 0.651 0.875 0.961 0.522 Den-Min CYSLT2R_A601G 0.037 0.042 0.102 0.002 Den-Min CYSLT2R_3P1 0.77 Asthma-1 CYSLT2R_3P2 0.12 Asthma-1 CYSLT2R_A601G 0.31 Asthma-1

[0068] (P values from TDT for Denmark and Minnesota and case control test for Asthma-1)

[0069] ASTHMA: Strict asthma

[0070] ATP_ASTH; Atopic asthma

[0071] BHR: Bronchial hyper-reactivity

[0072] PDA: Physician's diagnosis of asthma TABLE 3 Allele Frequency of CYSLT2R_A601G in Parents with Asthma or without Asthma (Denmark and Minnesota) Asthma (PDA) Number A/G G/G Frequency of G allele NO 457 30 0 3.28 YES 142 5 1 2.46

[0073] TABLE 4 Allele frequency of CYSLT2R_A601G in individuals with asthma or without asthma (Asthma-1) Asthma (PDA) Number A/G G/G Frequency of G allele NO 100 5 0 2.50 YES 200 5 0 1.25

[0074] TABLE 5 Linkage Disequilibrium Estimates Marker1 Marker2 Chi Squared p Value (Chi Sq.) LD Correlation R Minnesota CYSLT2R_3P1 CYSLT2R_3P2 14.281 0.000157443 0.304523 CYSLT2R_3P1 CYSLT2R_A601G 11.0162 0.000903191 0.266594 CYSLT2R_3P2 CYSLT2R_A601G 1.63404 0.201141 0.102019 Denmark CYSLT2R_3P1 CYSLT2R_3P2 41.0963 1.45E−10 0.297928 CYSLT2R_3P1 CYSLT2R_A601G 4.09937 0.0428993 0.0938927 CYSLT2R_3P2 CYSLT2R_A601G 3.63906 0.0564388 0.087899 DenMin CYSLT2R_3P1 CYSLT2R_3P2 55.067 1.16E−13 0.298747 CYSLT2R_3P1 CYSLT2R_A601G 12.288 0.000455885 0.140781 CYSLT2R_3P2 CYSLT2R_A601G 5.24756 0.0219776 0.0914111 Asthma-1 CYSLT2R_3P1 CYSLT2R_3P2 35.643 2.37E−09 0.348782 CYSLT2R_3P1 CYSLT2R_A601G 4.69565 0.0302391 0.126811 CYSLT2R_3P2 CYSLT2R_A601G 0.275975 0.599352 0.0303808 Pooled CYSLT2R_3P1 CYSLT2R_3P2 89.9028 2.50E−21 0.314316 CYSLT2R_3P1 CYSLT2R_A601G 16.4589 4.97E−05 0.134339 CYSLT2R_3P2 CYSLT2R_A601G 3.22997 0.0723019 0.0590282

[0075]

1 14 1 3300 DNA Homo sapiens CDS (264)..(1304) 1 aagttctcta agtttgaagc gtcagcttca accaaacaaa ttaatggcta ttctacattc 60 aaaaatcagg aaatttaaat ttattatgaa atgtaatgca gcatgtagta aagacttaac 120 cagtgtttta aaactcaact ttcaaagaaa agatagtatt gctccctgtt tcattaaaac 180 ctagagagat gtaatcagta agcaagaagg aaaaagggaa attcacaaag taactttttg 240 tgtctgtttc tttttaaccc agc atg gag aga aaa ttt atg tcc ttg caa cca 293 Met Glu Arg Lys Phe Met Ser Leu Gln Pro 1 5 10 tcc atc tcc gta tca gaa atg gaa cca aat ggc acc ttc agc aat aac 341 Ser Ile Ser Val Ser Glu Met Glu Pro Asn Gly Thr Phe Ser Asn Asn 15 20 25 aac agc agg aac tgc aca att gaa aac ttc aag aga gaa ttt ttc cca 389 Asn Ser Arg Asn Cys Thr Ile Glu Asn Phe Lys Arg Glu Phe Phe Pro 30 35 40 att gta tat ctg ata ata ttt ttc tgg gga gtc ttg gga aat ggg ttg 437 Ile Val Tyr Leu Ile Ile Phe Phe Trp Gly Val Leu Gly Asn Gly Leu 45 50 55 tcc ata tat gtt ttc ctg cag cct tat aag aag tcc aca tct gtg aac 485 Ser Ile Tyr Val Phe Leu Gln Pro Tyr Lys Lys Ser Thr Ser Val Asn 60 65 70 gtt ttc atg cta aat ctg gcc att tca gat ctc ctg ttc ata agc acg 533 Val Phe Met Leu Asn Leu Ala Ile Ser Asp Leu Leu Phe Ile Ser Thr 75 80 85 90 ctt ccc ttc agg gct gac tat tat ctt aga ggc tcc aat tgg ata ttt 581 Leu Pro Phe Arg Ala Asp Tyr Tyr Leu Arg Gly Ser Asn Trp Ile Phe 95 100 105 gga gac ctg gcc tgc agg att atg tct tat tcc ttg tat gtc aac atg 629 Gly Asp Leu Ala Cys Arg Ile Met Ser Tyr Ser Leu Tyr Val Asn Met 110 115 120 tac agc agt att tat ttc ctg acc gtg ctg agt gtt gtg cgt ttc ctg 677 Tyr Ser Ser Ile Tyr Phe Leu Thr Val Leu Ser Val Val Arg Phe Leu 125 130 135 gca atg gtt cac ccc ttt cgg ctt ctg cat gtc acc agc atc agg agt 725 Ala Met Val His Pro Phe Arg Leu Leu His Val Thr Ser Ile Arg Ser 140 145 150 gcc tgg atc ctc tgt ggg atc ata tgg atc ctt atc atg gct tcc tca 773 Ala Trp Ile Leu Cys Gly Ile Ile Trp Ile Leu Ile Met Ala Ser Ser 155 160 165 170 ata atg ctc ctg gac agt ggc tct gag cag aac ggc agt gtc aca tca 821 Ile Met Leu Leu Asp Ser Gly Ser Glu Gln Asn Gly Ser Val Thr Ser 175 180 185 tgc tta gag ctg aat ctc tat aaa att gct aag ctg cag acc atg aac 869 Cys Leu Glu Leu Asn Leu Tyr Lys Ile Ala Lys Leu Gln Thr Met Asn 190 195 200 tat att gcc ttg gtg gtg ggc tgc ctg ctg cca ttt ttc aca ctc agc 917 Tyr Ile Ala Leu Val Val Gly Cys Leu Leu Pro Phe Phe Thr Leu Ser 205 210 215 atc tgt tat ctg ctg atc att cgg gtt ctg tta aaa gtg gag gtc cca 965 Ile Cys Tyr Leu Leu Ile Ile Arg Val Leu Leu Lys Val Glu Val Pro 220 225 230 gaa tcg ggg ctg cgg gtt tct cac agg aag gca ctg acc acc atc atc 1013 Glu Ser Gly Leu Arg Val Ser His Arg Lys Ala Leu Thr Thr Ile Ile 235 240 245 250 atc acc ttg atc atc ttc ttc ttg tgt ttc ctg ccc tat cac aca ctg 1061 Ile Thr Leu Ile Ile Phe Phe Leu Cys Phe Leu Pro Tyr His Thr Leu 255 260 265 agg acc gtc cac ttg acg aca tgg aaa gtg ggt tta tgc aaa gac aga 1109 Arg Thr Val His Leu Thr Thr Trp Lys Val Gly Leu Cys Lys Asp Arg 270 275 280 ctg cat aaa gct ttg gtt atc aca ctg gcc ttg gca gca gcc aat gcc 1157 Leu His Lys Ala Leu Val Ile Thr Leu Ala Leu Ala Ala Ala Asn Ala 285 290 295 tgc ttc aat cct ctg ctc tat tac ttt gct ggg gag aat ttt aag gac 1205 Cys Phe Asn Pro Leu Leu Tyr Tyr Phe Ala Gly Glu Asn Phe Lys Asp 300 305 310 aga cta aag tct gca ctc aga aaa ggc cat cca cag aag gca aag aca 1253 Arg Leu Lys Ser Ala Leu Arg Lys Gly His Pro Gln Lys Ala Lys Thr 315 320 325 330 aag tgt gtt ttc cct gtt agt gtg tgg ttg aga aag gaa aca aga gta 1301 Lys Cys Val Phe Pro Val Ser Val Trp Leu Arg Lys Glu Thr Arg Val 335 340 345 taa ggagctctta gatgagacct gttcttgtat ccttgtgtcc atcttcattc 1354 actcatagtc tccaaatgac tttgtattta catcactccc aacaaatgtt gattcttaat 1414 atttagttga ccattacttt tgttaataag acctacttca aaaattttat tcagtgtatt 1474 ttcagttgtt gagtcttaat gagggataca ggaggaaaaa tccctactag agtcctgtgg 1534 gctgaaatat cagactggga aaaaatgcaa agcacattgg atcctacttt tcttcagata 1594 ttgaaccaga tctctggccc atcaggcttt ctaaattctt caaaagagcc acaacttccc 1654 cagcttctcc agctcccctg tcctcttcaa tcccttgaga tatagcaact aacgacgcta 1714 ctggaagccc cagagcagaa aagaagcaca tcctaagatt cagggaaaga ctaactgtga 1774 aaaggaaggc tgtcctataa caaagcagca tcaagtccca agtaaggaca gtgagagaaa 1834 agggggagaa ggattggagc aaaagagaac tggcaataag taggggaagg aagaatttca 1894 ttttgcattg ggagagaggt tctaacacac tgaaggcaac cctatttcta ctgtttctct 1954 cttgccaggg tattaggaag gacaggaaaa gtaggaggag gatctggggc attgccctag 2014 gaaatgaaag aattgtgtat agaatggaag ggggatcatc aaggacatgt atctcaaatt 2074 ttctttgaga tgcaggttag ttgaccttgc tgcagttctc cttcccatta attcattggg 2134 atggaagcca aaaataaaag aggtgcctct gaggattagg gttgagcact caagggaaag 2194 atggagtaga gggcaaatag caaaagttgt tgcactcctg aaattctatt aacatttccg 2254 cagaagatga gtagggagat gctgccttcc cttttgagat agtgtagaaa aacactagat 2314 agtgtgagag gttcctttct gtccattgaa acaaggctaa ggatactacc aactactatc 2374 accatgacca ttgtactgac aacaattgaa tgcagtctcc ctgcagggca gattatgcca 2434 ggcactttac atttgttgat cccatttgac attcacacca aagctctgag ttccatttta 2494 cagctgaaga aattgaagct tagagaaatt aagaagcttg tttaagttta cacagctagt 2554 aagagtttta aaaatctctg tgcagaagtg ttggctgggt gctctcccca ccactaccct 2614 tgtaaacttc caggaagatt ggttgaaagt ctgaataaaa gctgtccttt cctaccaatt 2674 tcctccccct cctcactctc acaagaaaac caaaagtttc tcttcagagt tgttgactca 2734 tagtacagta aagggtggag gtgatatggc attctgaaag tagggaggga ctaagtcagt 2794 cgtcatacta aacaaaaatc ccagtaccct ttccttattt agctaccaga atgatgacag 2854 acagactcaa accctgtcaa gacaggaccc tggaggatcc tcctatgggg aaactgcata 2914 atctgaaaaa aaggctgaca gatacaaata gttgaggatc cttcaacaca aaagctgcgt 2974 gtctgcccta ttactcacct gacgatgaag cccacaatgc aacaaatccc ttccactcac 3034 agcatttggt caacctgtca gagcctcatt cttaattatg aaaagtagtc aatgaacaca 3094 atacatttga gggaaaggcc gtaacatgaa aggcaccaac aaataaatgt gagagtagat 3154 agataccttt tgagtataaa agatcctcca aaataagaga ttaaaccaag atagaggaaa 3214 acacagtagc tgggaaacaa ggaatccaac gcaggagaaa gtgaagagaa ttcccaggat 3274 gttggtgtgt agcaggctta gaaagc 3300 2 346 PRT Homo sapiens 2 Met Glu Arg Lys Phe Met Ser Leu Gln Pro Ser Ile Ser Val Ser Glu 1 5 10 15 Met Glu Pro Asn Gly Thr Phe Ser Asn Asn Asn Ser Arg Asn Cys Thr 20 25 30 Ile Glu Asn Phe Lys Arg Glu Phe Phe Pro Ile Val Tyr Leu Ile Ile 35 40 45 Phe Phe Trp Gly Val Leu Gly Asn Gly Leu Ser Ile Tyr Val Phe Leu 50 55 60 Gln Pro Tyr Lys Lys Ser Thr Ser Val Asn Val Phe Met Leu Asn Leu 65 70 75 80 Ala Ile Ser Asp Leu Leu Phe Ile Ser Thr Leu Pro Phe Arg Ala Asp 85 90 95 Tyr Tyr Leu Arg Gly Ser Asn Trp Ile Phe Gly Asp Leu Ala Cys Arg 100 105 110 Ile Met Ser Tyr Ser Leu Tyr Val Asn Met Tyr Ser Ser Ile Tyr Phe 115 120 125 Leu Thr Val Leu Ser Val Val Arg Phe Leu Ala Met Val His Pro Phe 130 135 140 Arg Leu Leu His Val Thr Ser Ile Arg Ser Ala Trp Ile Leu Cys Gly 145 150 155 160 Ile Ile Trp Ile Leu Ile Met Ala Ser Ser Ile Met Leu Leu Asp Ser 165 170 175 Gly Ser Glu Gln Asn Gly Ser Val Thr Ser Cys Leu Glu Leu Asn Leu 180 185 190 Tyr Lys Ile Ala Lys Leu Gln Thr Met Asn Tyr Ile Ala Leu Val Val 195 200 205 Gly Cys Leu Leu Pro Phe Phe Thr Leu Ser Ile Cys Tyr Leu Leu Ile 210 215 220 Ile Arg Val Leu Leu Lys Val Glu Val Pro Glu Ser Gly Leu Arg Val 225 230 235 240 Ser His Arg Lys Ala Leu Thr Thr Ile Ile Ile Thr Leu Ile Ile Phe 245 250 255 Phe Leu Cys Phe Leu Pro Tyr His Thr Leu Arg Thr Val His Leu Thr 260 265 270 Thr Trp Lys Val Gly Leu Cys Lys Asp Arg Leu His Lys Ala Leu Val 275 280 285 Ile Thr Leu Ala Leu Ala Ala Ala Asn Ala Cys Phe Asn Pro Leu Leu 290 295 300 Tyr Tyr Phe Ala Gly Glu Asn Phe Lys Asp Arg Leu Lys Ser Ala Leu 305 310 315 320 Arg Lys Gly His Pro Gln Lys Ala Lys Thr Lys Cys Val Phe Pro Val 325 330 335 Ser Val Trp Leu Arg Lys Glu Thr Arg Val 340 345 3 32 DNA Artificial Sequence Synthetic Construct 3 actaagtcag tcatcatact aaacaaaaat cc 32 4 31 DNA Artificial Sequence Synthetic Construct 4 actaagtcag tcgtcatact aaacaaaaat c 31 5 21 DNA Artificial Sequence Synthetic Construct 5 gggtggaggt gatatggcat t 21 6 25 DNA Artificial Sequence Synthetic Construct 6 tctgtctgtc atcattctgg tagct 25 7 27 DNA Artificial Sequence Synthetic Construct 7 ttgaggatcc ttcaacacaa aagctgc 27 8 26 DNA Artificial Sequence Synthetic Construct 8 ttgaggatcc ttcagcacaa aagctg 26 9 25 DNA Artificial Sequence Synthetic Construct 9 agacagactc aaaccctgtc aagac 25 10 25 DNA Artificial Sequence Synthetic Construct 10 gcttcatcgt caggtgagta atagg 25 11 30 DNA Artificial Sequence Synthetic Construct 11 tgctaagctg cagaccatga actatattgc 30 12 29 DNA Artificial Sequence Synthetic Construct 12 ctaagctgca gaccgtgaac tatattgcc 29 13 25 DNA Artificial Sequence Synthetic Construct 13 cacatcatgc ttagagctga atctc 25 14 26 DNA Artificial Sequence Synthetic Construct 14 cagataacag atgctgagtg tgaaaa 26 

That which is claimed is:
 1. A method of identifying a subject at increased risk of asthma, comprising detecting the allelic forms of the A601 G polymorphism in the Cysteinyl leukotriene 2 receptor gene, where a person homozygous for the A allele is at increased risk for asthma compared to a subject with at least one G allele.
 2. A method according to claim 1 where the subject is a member of a family having at least one member diagnosed with asthma.
 3. A method of stratifying a population receiving pharmaceutical treatment for asthma to detect differences in phenotypic response to the pharmaceutical treatment, by: (a) genotyping a population of subjects in need of pharmaceutical treatment for asthma, to determine each subject's allelic forms of the A601G polymorphism in the Cysteinyl leukotriene 2 receptor gene; (b) administering to said subjects a pharmaceutical treatment for asthma; (c) correlating each subject's phenotypic response to treatment with the subject's genotype, to detect phenotypic responses that are associated with said allelic forms. 